外源性 SPARC 通过与整合素 β1 相互作用抑制前列腺癌细胞的增殖和迁移。

Exogenous SPARC suppresses proliferation and migration of prostate cancer by interacting with integrin β1.

机构信息

Department of Integrative Cancer Therapy and Urology, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Ishikawa, Japan.

出版信息

Prostate. 2013 Aug;73(11):1159-70. doi: 10.1002/pros.22664. Epub 2013 Mar 26.

DOI:10.1002/pros.22664

PMID:23532895

Abstract

BACKGROUND

The matricellular protein secreted protein acidic and rich in cysteine (SPARC) plays an important role on tumor metastasis and progression in several cancers. However, the roles of SPARC in prostate cancer (PCa) remain unclear.

METHODS

To identify SPARC protein in prostate tissue, immunohistochemical analysis of SPARC was conducted using human prostate tissue microarray. To detect SPARC expression in prostate cancer (LNCaP, DU145, and PC-3) and stromal cells, RT-PCR, western blot analysis, and ELISA was conducted. To reveal the function of exogenous SPARC in PCa cells, AKT phosphorylation was confirmed by western blot analysis after coculture with stromal cells. Proliferation and migration of PCa cells were examined by addition of SPARC. The interaction between SPARC and integrin β1 was confirmed by western blot analysis after immunoprecipitation.

RESULTS

SPARC protein was expressed well in normal tissue compared with PCa tissue. ELISA showed high secreted SPARC protein in normal prostate-derived stromal cell (PrSC) compared with PCa-derived stromal cell (PCaSC) and PCa. PCa cells cocultured with PrSC showed reduced AKT phosphorylation more than with PCaSC. PCa cells cocultured with PrSC whose SPARC was knocked-down restored AKT phosphorylation. Moreover, PCa cells treated with SPARC led to reduced AKT phosphorylation. Immunoprecipitation with SPARC revealed interaction of SPARC and integrin β1 in PCa cells. Inhibited proliferation and migration of PCa cells by SPARC was restored by integrin β1 neutralizing antibody.

CONCLUSIONS

Reduced SPARC secretion from stromal cells might affect PCa progression mediating through limiting AKT phosphorylation after interaction with integrin β1.

摘要

背景

细胞外基质糖蛋白分泌型酸性富含半胱氨酸蛋白（SPARC）在几种癌症的肿瘤转移和进展中发挥着重要作用。然而，SPARC 在前列腺癌（PCa）中的作用尚不清楚。

方法

使用人前列腺组织微阵列进行免疫组织化学分析，以鉴定前列腺组织中的 SPARC 蛋白。为了检测前列腺癌（LNCaP、DU145 和 PC-3）和基质细胞中的 SPARC 表达，进行了 RT-PCR、western blot 分析和 ELISA。为了揭示外源性 SPARC 在 PCa 细胞中的功能，通过与基质细胞共培养后进行 western blot 分析来确认 AKT 磷酸化。通过添加 SPARC 来检测 PCa 细胞的增殖和迁移。通过免疫沉淀后的 western blot 分析来确认 SPARC 与整合素 β1 的相互作用。

结果

与 PCa 组织相比，SPARC 蛋白在正常组织中表达良好。ELISA 显示正常前列腺衍生基质细胞（PrSC）中分泌的 SPARC 蛋白明显高于 PCa 衍生基质细胞（PCaSC）和 PCa。与 PCaSC 相比，与 PrSC 共培养的 PCa 细胞显示出更低的 AKT 磷酸化。与 PrSC 共培养且 SPARC 被敲低的 PCa 细胞恢复了 AKT 磷酸化。此外，用 SPARC 处理 PCa 细胞会导致 AKT 磷酸化减少。用 SPARC 进行免疫沉淀显示 SPARC 和整合素 β1 在 PCa 细胞中的相互作用。用整合素 β1 中和抗体恢复了 SPARC 抑制的 PCa 细胞的增殖和迁移。